Final answer:
The limiting reagent in the reaction to produce sodium chloride from sodium and chlorine is chlorine gas (Cl2), as it is present in stoichiometrically lesser amount relative to sodium, with 1.5 moles of sodium remaining unreacted after the reaction.
Step-by-step explanation:
To determine the limiting reagent in the reaction of sodium and chlorine to produce sodium chloride (NaCl), the balanced chemical equation must be written first. The balanced equation is 2 Na + Cl2 → 2 NaCl. Here, 2 moles of sodium (Na) react with 1 mole of chlorine gas (Cl2) to produce 2 moles of sodium chloride (NaCl). With 3 moles of sodium and 3 moles of chlorine provided, chlorine gas is in a lesser amount stoichiometrically because it would need 6 moles to react with 3 moles of sodium. Therefore, chlorine gas (Cl2) is the limiting reagent, and sodium is in excess.
After the reaction, for every mole of Cl2 that reacts, 2 moles of Na are consumed. Since we started with equal moles of Na and Cl2, no moles of chlorine would remain, because 3 moles of Na would only require 1.5 moles of Cl2 to react completely. Hence, at the end of the reaction, 1.5 moles of sodium would remain unreacted, and all the chlorine would be used up, confirming again that chlorine is the limiting reagent.